The interrelationship between speeded and unspeeded divergent thinking and reasoning, and the role of mental speed

The relationship between intelligence and creativity is still subject to substantial debate in the research literature. In the present study, we focused on core dimensions of both constructs, that is divergent thinking and reasoning. We hypothesized their relationship to depend both on the speededness of test tasks and on the subject's mental speed, positing that with increasing speededness of the tasks, mental speed would have a stronger impact on task outcomes. We disentangled the effects of task speededness and mental speed experimentally, testing 261 participants (mean age 14.48 years) with 12 divergent thinking and 12 reasoning tasks, 6 of each under power conditions, 6 time-constrained. In addition, we assessed mental speed with 6 tasks. We analyzed the data through structural equation modeling. Results confirmed our expectations: test speededness contributed significantly to mental speed variance in divergent thinking task performance. Divergent thinking assessed under time constraints was fully explained by divergent thinking assessed under power conditions and by mental speed. Divergent thinking and reasoning showed no correlation when controlling for mental speed. Our findings suggest that the correlations between divergent thinking and reasoning are mainly the result of variance both constructs share with mental speed, and that timed versus untimed test-taking plays a minor role.